Punching machine and structure therefor



1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1, 1960 8 Sheets-Sheet 1 M M/ MTORNEYS Dec. 28, 1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR 8 Sheets-Sheet 2 Filed NOV. 1. 1960 M W 9 7 ATTORNEYS Dec. 28, 1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR 8 Sheets-Sheet 5 Filed Nov. 1, 195

n l I I TTORNE YS Dec. 2, 1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1, 1960 8 Sheets-Sheet 4 A5? INVENTORS M W, ,1 TTORNEYS 1965 A. K. scHoTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1, 1960 8 Sheets-Sheet 5 IN VEN TORS 449W? (SC/9077' M/V/Vff? 54197654 BY (6%?![9 ([6 30/007 A TTORNE YS Dec. 28, 1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1, 1960 8 Sheets-Sheet 6 1965 A. K. SCHOTT ETAL 3,225,536

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1. 1960 8 Sheets-Sheet 7 "& W 7.- 1n

IN V EN TORS 42590? 4 6677077 mil/Z 1 542W M 7%,; ATTORNEYS ec. 28, 1965 A. K. SCHOTT ETAL 3,225,636

PUNCHING MACHINE AND STRUCTURE THEREFOR Filed Nov. 1, 1960 8 Sheets-Sheet 8 VIIIIIII/YIIIIIIIIIIYI/I/ A 'INVENTORS Aer/904 4 \szwarr United States Patent Office 3,225,636 Fatented Dec. 28, 1965 3,225,636 PUNCHING MACHINE AND STRUCTURE THEREFOR Arthur K. Schott, Kenmore, Kenneth J. Bartha, Tona- Wanda, and Charles Lee Rovoldt, Getzville, N.Y., as-

siguors to Houdaille Industries, Inc., Bufialo, N.Y., a

corporation of Michigan Filed Nov. 1, 1960, Ser. No. 66,639 33 Claims. (Cl. 83-468) This invention relates generally to punching machines, and more specifically to an improved punching machine embodying numerous novel coacting features, combinations, and sub-combinations thereof.

Although the principles of the present invention may be included in various punching machines and devices, a particularly useful application is made in a punching machine of the type of that acts on a single workpiece, the workpiece being positioned by either adjustable gaging carried on the machine, or by a template follower, the machine being provided with appropriate punch and die means for effecting punching, notching, and nibbling on the workpiece.

The present invention contemplates the utilization of a workpiece-supporting table which is vertically adjustable with respect to the punch and die means, the table being provided with gaging structure engageable with adjacent edges of a workpiece and adapted to indicate desired dimensions numerically directly. A further important feature of the instant invention includes a pair of pivotable clamping mechanisms by which a tool support is maintained and returned, when removed, to a position of alignment with other tooling, to a position corresponding to its own prior position, and to a position wherein relationships established by the gaging mechanism is maintained. The punching machine of the present invention also includes a novel punch and stripper assembly adapted to accommodate punches of shaped or non-circular cross-section, together with means for orienting the punch and die to any selected angular position about the punching axis. This feature requires novel keying structure and alignment tooling which is also provided herein. The electrical control circuit is adapted to effect both single stroke operation and continuous or nibbling operation, and is provided with interlock means between it and the means by which the punch and die means are aligned to insure that the machine may only be operated when everything is in proper adjustment.

Accordingly, it is an object of the present invention to provide an improved punching machine.

Another object of the present invention is to provide a punching machine embodying numerous novel coacting features, combinations, and sub-combinations thereof.

Yet another object of the present invention is to provide a novel clamping structure for a tool support which structure maintains various relationships between features of the punching machine of this invention.

A still further object of the present invention is to provide a novel clamping structure.

A still further object of the present invention is to provide gaging structure for accurately positioning the workpiece to be worked on in relation to a predetermined point.

Many other advantages, features, and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by Way of illustrative example.

On the drawings:

FIGURE 1 is a perspective view of a punching machine provided in accordance with the principles of the present invention;

FIGURE 2 is an enlarged front elevational view of the punching machine of FIGURE 1 with certain parts removed therefrom;

FIGURE 3 is an enlarged view of the sub-table and die taken generally along line IIIIII of FIGURE 2;

FIGURE 4 is an enlarged sectional fragmentary view taken along line IVIV of FIGURE 3;

FIGURE 5 is an enlarged sectional view of a die and supporting structure therefor taken generally along line VV of FIGURE 1;

FIGURE 6 is an enlarged cross-sectional view of a punch and stripping assembly taken along line VI-VI of FIGURE 1;

FIGURE 7 is an enlarged sectional View taken along the lines VV and VIVI of FIGURE 1 with aligning tools substituted for the punch and die means;

FIGURE 8 is a fragmentary top view of the structure shown in FIGURE 7;

FIGURE 9 is a cross-sectional view of a pedestal die supported on structure shown in FIGURE 5;

FIGURE 10 is a cross-sectional view of a punch and die mechanism, the die being supported byan adaptor on the structure shown in FIGURE 5, and the punch being supported on a tool support of a size smaller than described heretofore herein;

FIGURE 11 is a cross-sectional view taken along line XI--XI of FIGURE 10;

FIGURE 12 is an enlarged fragmentary perspective view of a portion of FIGURE 1 showing a clamping mechanism;

FIGURE 13 shows the structure of FIGURE 12 with the major components thereof disconnected;

FIGURE 14 is an enlarged sectional view taken along line XIVXIV of FIGURE 12;

FIGURE 15 corresponds to FIGURE 14 with the components illustrated in the position that they are placed immediately prior to a disconnection such as shown in FIGURE 13;

FIGURE 16 is an enlarged fragmentary cross-sectional view taken along line XVIXVI of FIGURE 15;

FIGURE 17 on sheet 3 is an enlarged front view, partly in section, taken along line XVII-XVII of FIG- URE 1, and illustrating certain gaging structure;

FIGURE 18 on sheet 4 is an enlarged cross-sectional view taken along line XVIIIXVIII on FIGURE 17;

FIGURE 19 is an enlarged cross-sectional view taken generally along the broken line XIXXIX on FIG- URE 17;

FIGURE 20 on sheet 8 is an enlarged cross-sectional view of certain gage clamping structure taken along line XXXX of FIGURE 1;

FIGURE 21 is an enlarged sectional view taken along line XXIXX-I of FIGURE 20;

FIGURE 22 is a fragmentary portion of FIGURE 20 showing certain parts in a retracted position;

FIGURE 23 is an enlarged sectional view taken along line XXIIIXXIII of FIGURE 1;

FIGURE 24 is a fragmentary front elevational view taken along line XXIV-XXIV of FIGURE 1, partly in section, showing a gaging indicating mechanism;

FIGURE 25 is an enlarged fragmentary cross-sectional view taken along line XXVXXV of FIGURE 2 and showing a gage clamping mechanism;

FIGURE 26 on sheet 1 is an enlarged fragmentary cross-sectional view taken along line XXV'IXXVI of FIGURE 1; and

FIGURE 27 is a schematic diagram of the electrical 3 circuit employed to operate the machine shown in FIG- URE 1.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a punching machine such as illustrated in FIGURE 1, generally indicated by the numeral 30. The machine includes a rigid frame 31 of both hollow an C-shaped construction having an upper arm 31a and a lower arm 31b. The lower arm 31b is provided with a pair of bases 32, 32 which support the frame 31 on the floor. Also prominent in FIGURE 1 is [a horizontal workpiece-supporting table 33 supported in a manner presently to be described. To the table 33 there is secured adjustable gaging means generally indicated at 34, and to be described in detail later herein. Certain components of the device are covered by an upper shroud 35 and a lower shroud 36, a control panel 37 being secured to the upper arm 31.

Referring now to FIGURE 2, there is shown a front elevational view of the structure of FIGURE 1 wherein the upper shroud 35, the control panel 37, the lower shroud 36, and the gaging 34 have been removed for clarity of illustration. On the lower arm 31b of the frame 31 there is provided a bed 38 on which tooling means such as the die 39 are supported. In alignment with the die 39, there is a punch and stripping assembly generally indicated at 40 which is supported by an upper tool support generally indicated at 41 which is secured to the frame 31 by a pair of clamping mechanisms generally indicated at 42 and 43. It will be noted that the upper tool support 41 comprises a generally U-shaped member or yoke having spaced arms 41a, 41b extending along opposite sides of the tool 40 supported on a bight 410 which connects the arms 41a and 41b.

Also disposed between the arms 41a and 41b is a ram 44 which is reciprocably driven. A motor shown diagrammatically in the circuit diagram of FIGURE 27 operates continually through belts to drive a pulley-flywheel assembly 45 which includes an eccentric 46 which continually reciprocates a shaft 47. The continuously reciprocating shaft 47 is selectably connected to the ram 44 by an electrically actuated press clutch 48 which includes a solenoid shown schematically in FIGURE 27. The structural details of the clutch are shown in the copending application of Arthur K. Schott and Charles E. Wilson on a Press Clutch, U.S. Serial No. 825,028, now US. Patent No. 2,979,905.

The workpiece-supporting table 33 is supported on the frame 31 by structure shown in FIGURES 2-4. Means are provided by which the table 33 may be vertically adjusted and by which the table 33 is locked against any horizontal or angular movement. To this end, a subtable assembly 49 is provided which includes a sub-table 50 which is apertured so that the bed 38 which supports the die 39 is independent thereof. The sub-table 50 is provided with a pair of generally U-shaped brackets 51, 52 which are welded thereto and which jointly comprise a saddle which rests on suitable bearing surfaces 53a, 53b, and 53c. Clamping screws 54 rigidly hold the sub-table assembly 49 in a fixed position with respect to the rigid frame 31. If desired, each of the U-shaped members 51, 52 may be provided with stiffening means 55. Attached to the lower surface of the sub-table 50, there are three suitable pads 56, 57, and 57, to each of which is attached a screw jack assembly 58. The detailed structure of each screw jack is known and forms no part of this invention. The screw jacks 58 each include a shaft 59 secured to the workpiece supporting table 33. Raising and lowering of the table 33 is effected by simultaneous operation of the various screw jacks 58. Each of the screw jacks 58 is connected by appropriate shafting to a sprocket wheel 60. A roller chain 61 connects the sprocket wheel together and to an additional sprocket wheel 62 which is supported on a shaft for co-rotation with a handle 63. When the jointly driven screw jacks are manually adjusted, operated, or actuated, the position of the table is adjusted vertically. It is thus apparent that the adjustment mechanism also secures and supports the table 33 on the subtable 49. By manipulation of the handle 63, the table 33 may be made coplanar with the upper surface of the die 39 as shown in FIGURE 1, a position which is particularly advantageous for fiat workpieces, and the table 33 may be vertically spaced from the die 39 as shown in FIGURE 2, a position which is particularly advantageous for punching certain channel forms and other non-fiat workpieces.

To keep the table 33 in laterally fixed position, to preclude both any lateral displacement and any angular movement about a vertical axis, there is provided a pair of guide pins 64. Each guide pin 64 is secured to a support ring 65 by a pin 66, the support ring 65 being secured to the table 33 by a screw and pin arrangement. The guide pin 64 is slidably received in a guide bushing 67 which is secured to the sub-table 50 by a similar screw and pin arrangement extending through a pad corresponding to the pad 56. The guide pin 64 is provided with a stop ring 68 of the snap-ring type which limits upward movement or adjustment of the table 33.

One purpose for adjusting the table 33 so that its upper surface is coplanar with the die 39 is to provide adequate support for the workpiece so as to be able to position it accurately and also so as to position it coplanarly with the die 39. In practice, it has been found that some oil will be present quite frequently on the workpiece, a fact which makes picking up the finished workpiece from the table 33 even more difficult than may be expected. By rotation of the crank 63, the table 33 may be lowered slightly independently of the die support means so that the die will act on the unpunched portion of the workpiece to raise the same from the upper surface of the table 33 to facilitate grasping the same. Thus the table adjusting mechanism comprises selectively actuatable means for effecting relative vertical movement between the tool supported on the bed 38 and the table 33 to space the work piece upwardly from the table 33 to facilitate grasping and to overcome the folding force of any oil present.

Referring now to FIGURE 5, there is shown the structure by which the lower tool or die 39 is supported. The lower tool support or die support comprise components which are rigidly secured to the lower arm 31b of the frame 31. These include the bed generally indicated at 38 which includes a bed pad 69 welded to the frame 31 independently of the sub-table 50 which is spaced from the workpiece supporting table 33. To the bed pad 69 there is secured a bed block 70, by a plurality of screws such as 71. The bed block has an upwardly directed circular recess 72 in which is received a cylindrical member 73 which is secured to the bed block 70 by a plurality of screws such as 74. Within the cylindrical member 73, there is slidably supported and received a slidable element 75 which also rests at its lower end on the bed block 70 within the recess 72 as shown. The axial extent of the sliding element 75 is less than the axial extent of the cylindrical member 73 so that at their upper ends, they jointly define a nest-like tool receiving structure within which the die 39 is supported. To this end, the slidably mounted element or member 75 is normally stationary, but means are provided to selectively reciprocate it. To this end, there is provided a pin 76 which is guided in the bed 38 for reciprocation. A horizontal shaft 77 is rocka bly guided in the lower arm 31b of the frame 31, and at its inner end is provided with an eccentric or cam 82 by which the pin 76 is selectively reciprocated. To the outer end of the shaft 77 there is provided a handle 78, seen also in FIGURES 1 and 2, the shaft having an annular groove 79. A set screw 80 is received in the groove 79 to limit axial movement of the shaft 77. A stop pin 81 is carried by the shaft 77 in fixed alignment with the eccentric or cam end thereof 82 for abutting the set screw 80 at such an angular position that the eccentric 82 can never be positioned in dead center. Actuation of the handle 78 causes the eccentric 82 to raise the pin 76 which acts through the normally stationary member 75 to raise the tool or die 39. Raising the tool has a two-fold pumose. One of these is to facilitate removal of the tool from the nest defined by the upper end of members 73 and 75. A further purpose of this structure is to raise the workpiece from the upper surface of the workpiece supporting table 33, as already described, so that this mechanism constitutes not only a tool lifting means, but a selectively actutatable means for effecting relative vertical movement between the tool support on the bed and the table 33 to space the workpiece upwardly from the table 33. In this instance, as illustrated, there is effected an upward movement of the tool support means on the bed.

If the eccentric 82 were left in a raised dead-center position, and forgotten there, subsequent operation of the punching machine would likely damage the tool raising mechanism. Since the stop pin 81 prevents such positioning of the eccentric 82, even if the eccentric is left in a raised position during subsequent punch operation, the force acting on the slidable element or member 75 would merely return the eccentric to the illustrated position without damage to the same. To retain the slidable element 75 within the cylindrical member 73, there is provided a set screw 83 and slot 84 in the members 73 and 75. If desired, a liner 85a may be provided to guide punchings from the die 39.

In this embodiment, additional structure has been provided to accommodate shaped dies or tools. The term shaped as used herein refers to dies having cutting apertures and punches having cutting edges cooperating therewith which are of non-circular cross-section.

As best seen in FIGURE 3, the die 39 has been provided with a shaped opening of oblong configuration. When a shaped punch and die are employed, it is imperative that structure be provided to prevent rotation of the die. As best seen in FIGURE 5, and to this end, there is provided in the bed block 70 a radially extending keyway 85 which communicates with the recess 72. Likewise, the cylindrical member 73 has been provided with a radially extending keyway 86 aligned with the keyway 85, the keyways 85 and 86 jointly receiving a key 87 secured therein by a screw 88. The fits between these components is snug so that any rotation of the cylindrical member 73 about its axis is precluded by the key 87 acting jointly with the keyways 85 and 86. Similarly, the upper end of the cylindrical member 73 has been provided with a radial keyway 39, and the tool or die 39 has been provided with a keyway 90 aligned therewith. Within these keyways, there is received a key 91 which precludes any angular movement of the die 39 about the axis of the cylindrical member 73. A second keyway 92 may be provided in the tool or die 39 at a position spaced ninety-degrees from the keyway 90 to permit positioning the shaped opening thereof in a position spaced angularly ninety-degrees from that illustrated. Each of the keyways 90 and 92 extends in a direction parallel to the axis of the cylindrical member 73 throughout the length of the die 39, and the slidable pin 76 is receivable into the keyway 86, so that the provision of the keying structure does not in any way interfere with the die lifting mechanism.

In addition to these two preselected angular positions of the die 39, there is provided structure by which the die 39 may be keyed into any angular position. To this end, there is provided in the lower tool support, and more specifically in the cylindrical member 73, an upwardly directed recess 93 within which there is disposed an annular member or ring 94 to one side of which the key 91 is secured. When the ring 94 is inverted from the position shown, it will be apparent that the key 91 will still register with the keyway 90, but will not extend into the keyway 89. Thus when the annular member 94 is so inverted, the die 39 and the annular member 94 with its key 91 may rotate about the axis of the cylindrical member 73 to any selected position, and be there jointly locked by locking means comprising a series of screws 95. It is also to be noticed that when the die or tool 39 is so located, the die lifting mechanism still operates the same. Thus variously shaped punching means may be disposed and supported in a manner wherein each may be freely removed vertically for replacement with a tool of a different size or shape. Since the gaging structure is carried by the table 33 which is secured through the sub-table assembly 49 to the frame 31, and since the die 39 is thus also secured through the structure of FIG- URE 5 to the frame 31, it is apparent that the infinitely adjustable keying structure will lock a shaped die into a selected angular relationship with respect to the gaging structure 34. In FIGURE 3, the ring and key assembly 94, 91 has been shown in the inverted position which permits such universal keying.

In order for a shaped die to be adjustable about a vertical axis, it is necessary that the punch which is to cooperate therewith also be adjustable about the same axis. To this end, there is shown in FIGURE 6 a cooperating structure by which the punch and stripping assembly may be positioned at any selected angle about a vertical axis. The bight portion 410 of the upper tool support 41 has been provided with an upwardly directed recess 96 within which there is disposed a flange or ring portion of an annular member 97. Lock means comprising a group of screws 98 acts between the upper tool support 41 and the annular member 97 to lock the same in any selected angular position, thereby rendering the annular member 97 non-rotatable. A punch and guide assembly generally indicated at 99 is provided with keying presently to be described which corresponds in angular position to the keyways and 92 in the die 39 by which the punch and stripping assembly 99 is always angularly fixed with respect to the annular member 97 The punching and stripping assembly 99 includes a sleeve 100 which is vertically slidably received in the annular member 97. Within the sleeve 100, there is disposed a cylindrical punch driver 101 which is slidable within the hollow sleeve 100. At its lower end, the punch driver 101 has a concentric recess 102 which forms a part of its lower face and which has an axial opening 103 of smaller diameter than the diameter of the recess 102 whereby a shoulder 104 is defined which is directed downwardly or toward the die. A series of stripping springs 105 acts between the upper end of the sleeve 100 and a ring 106 which encircles the upper end of the punch driver 101 and which engages, with the punch driver 101, the lower surface of a punch head 107. The springs 105 urge the ring 106 against the head 107 and screws 108 retain the stripping springs 105 in the assembly. As such, the stripping springs 105 act between the punch driver 101 and the sleeve 100. There is also provided a punch bit 109 having a lower end 109a of a crosssection corresponding to that of the die 39, and an upper threaded end 109:5 received in the recess 102 in abutting relation with the shoulder 104, the shoulder 104 being a part of the lower face of the punch driver 101. Screw means 110 extend axially through the driver head 107 and driver 101 into threaded engagement with the upper end 10917 of the punch bit 109, so that these components move as a unit. .The annular member 97 is provided with an elongated keyway 111, and the punch driver is provided with an elongated keyway 112 which confront each other in spaced relation to each other with the sleeve 100 disposed therebetween. It is apparent that during operation, the annular member 97, being locked, is in effect a rigid part of the upper tool support 41. A key 113 is'rigidly secured in a radial aperture in the sleeve 100 and has ends which project radially therethrough and into the keyways 111, 112 with a close sliding fit. The punch driver 101 is thereby angularly keyed to the tool support 41. The punch driver 101 is provided with an additional keyway 114 which extends horizontally across the lower face of the punch driver and is aligned with a horizontally opening keyway 115 in the upper end 10912 of the punch bit 109. An additional key 116 is removably secured as by a screw to the punch driver 101 and is disposed in the keyways 114, 115 to angularly lock the position of the punch bit 109 with respect to the punch driver 101, thereby maintaining the angular relation of the punch as determined by the setting of the annular member 97. A series of lifting springs 117 acts between the annular portion 97 of the upper tool support 41 and the punch and stripping assembly 99 to bias the assembly as a unit away from the die. If desired, a stripping plate 118 maybe employed in the lower end of the stripping sleeve 100 and held therein by a spring clip 119 as shown. If such a stripping plate be employed, it is provided with an aperture closely corresponding in size and configuration to the punch bit 109 so as to engage the workpiece immediately adjacent to the peripheral edge thereof. It is thus apparent that the upper tool support is likewise adapted to support selectively-replaceable relatively-reciprocable tool means for cooperation with the tool means supported on the lower die support.

Where the punch bit 109 and the die 39 have shaped configurations, not only must the one be aligned and locked with the other to achieve interfitting, but the relative angular alignment must be made to a comparatively high degree of accuracy so that the peripheral clearance surrounding the punch bit 109 will be substantially uniform. To achieve this result, the die 39 and the punch and stripping assembly 99 are respectively slidably removed and replaced with a lower aligning tool 120 and an upper aligning tool 121 shown in FIGURE 7. The lower aligning tool 120 has an external configuration corresponding to the die 39 including a keyway 90a extending in a direction parallel to the axis of the slidable element 75, and corresponding to the keyway 90 in the die 39. The keyway 90a receives the key 91 carried by the annular member 94.

Similarly, the upper aligning tool 121 is provided with and supports a key 113a corresponding to the key 113 in the punch and stripping assembly 99, the key 113a being slidably received in the keyway 111 in the annular member 97. The lower aligning tool 120 is provided with a pair of upwardly extending alignment pins 122, and the lower edge or face of the alignment tool 121 is provided with slightly tapered grooves or recesses 123, 123 which receive the alignment pins 122.

Preferably the outside diameter of each of the alignment tools 120, 121 is made a few thousandths of an inch larger than the corresponding punch and die means, and the keyway 90a and key 113a likewise are sized to substantially eliminate freedom of lateral and angular movement. Owing to a wedging relation between the alignment pins 122 and mating grooves or slots 123, coupled with the substantial elimination of clearances, the alignment tools 120, and 121, when mated, comprise a rigid unit which is made to such precision that when the annular members 94 and 97 are positioned thereby and locked, any punch and die means inserted thereafter will cooperate with each other with a substantially uniform distribution of punch clearance about its periphery. It is thus apparent that the aligning tools are respectively received by the annular members and keyed by the corresponding keying structures, and are provided with interfitting structure directed toward the other for strict corotation, whereby alignment of the keying structures may be made accurately with respect to each other and locked.

Referring to FIGURE 8, it will be noted that the bight portion 410 of the upper tool support has been provided with indices such as 124, and that the upper face of the annular member 97 has been provided with mating indices such as 125 to cooperate therewith for indicating the relative angular position of the annular members with 8 respect to the punching machine and workpiece support table. In this illustration, the indices are arranged in a Vernier manner. I

By detaching the screws such as 74, shown in FIGURE 5, the cylindrical member 73 and the slidable element may be removed from the recess 72 of the bed block 70. In place thereof, as shown in FIGURE 9, there may be provided an upwardly extending rigid pedestal 126 which has a lower portion corresponding to the lower part of the cylindrical member 73 which fits in the same manner in the recess 72. Similarly, a keyway 86a receives the key 87 as before to provide angular orientation for use of shaped dies. Also shown in FIGURE 9 is a pedestal die 127 arranged to discharge slugs laterally from a shaped opening of T-shaped configuration. The die 127 is provided with a pair of horizontally directed keyways 128, 128, and the upper face of the pedestal 126 is provided with a keyway 129 adapted toreceive a key 130 at either end thereof for selectively registering with one of the keyways 128. The key 130 is held in a locked position by a screw 131. It is thus apparent that the die 127 may be angularly locked in any one of four positions. The die 127 may be replaced by other pedestal dies during operation of the device. Preferably, the pedestal 126 includes an axial aperture so that a die locking screw 132a may be employed when desired, as shown.

By use of a pedestal die support 126 and pedestal die 127, the punching machine 30 may be adapted to perforate channels and other formed workpieces. Thus the workpiece supporting table 33 may be lowered to a point where it would engage the top of the screw 88, thereby causing the die 127 to project a substantial distance from the workpiece supporting surface.

It is apparent that the punch and stripping assembly 99 of FIGURE 6 may be employed with an appropriately shaped punch bit to cooperate with the structure of FIG- URE 9. However, the structure of FIGURE 9 is particularly advantageous with dies having a relatively small cutting aperture. Accordingly, there is provided additional structure such as shown in FIGURES 10 and 11 which is particularly adapted to use smaller sized punches. This structure includes an additional upper tool support 132 having arms 132a and 13% extending upwardly on opposite sides of the ram 48, and having a bight portion 132a which receives and slidably supports a punch and stripper assembly 133. To this end, the upper tool support 132 is provided with an upwardly opening recess 134 in which there is disposed an annular member 135 which is rotatable about its axis to any selected angular position. Locking screws 136a are provided in the bight portion 132a to lock the position of the annular member 135. In the annular member 135 there is provided a vertically extending keyway 136 which receives a key 137 rigidly secured to a punch 138. The punching and stripping assembly 133 includes the punch 138 which is slidably supported at an enlarged central portion by the inner surface of a sleeve 139 which is slidably guided at its outer surface by the inner surface of the annular member 135. The punch 138 has a lower end portion 138a of oval configuration, and a threaded stem portion 139 surmounted by a punch head 140 secured thereto and locked thereto by a set screw 141. The upper end of the sleeve 139 is provided with a downwardly directed shoulder 139a, and a spacer 142 rests on the upper end of the sleeve 139. A pair of stripping springs 143, 144 acts between the punch head 140* and the spacer 142 to retract the punch 138 from the workpiece into the sleeve 139. In this structure, there is also provided an apertured lifting plate 145 which receives the sleeve 139, the upper surface of the lifting plate 145 engaging the shoulder 139a at a point remote from the lower end of the sleeve. Lifting spring means 146 act between the lifting plate 145 and the upper tool support 132 at a point adjacent to the recess 134. A pair of preloading and guiding screws 147, 147 serve to keep the plate 145 from rotating. The

punching and stripping assembly 133 together with the annular member 135 is rotatable as a unit with respect to the lifting plate 145 to any selected angular position. The upper surface of the annular member 135 is also provided with a set of indices 148 for indicating the angular position. These are shown in FIGURE 11. The annular member 135 is provided with two of the vertically extending keyways 136 so that the key 137 may he received in either of two angularly spaced positions for each locked position of the member 135.

The small dies may also .be employed with relatively smaller punches by placing an adapter ring 149 in the nest defined by the cylindrical member 73 and slidable element 75. The outer periphery of the adapter member 149 is substantially similar to that of the die 39, and is provided with a vertically extending keyway 90b in which the key 91 is received. Thus the adapter ring may be locked in a fixed preselected position when the annular member 94 has its key 91 directed downwardly as shown in FIGURE 5, or the adapter ring may be set to any selected angular position and locked, when arranged as shown in FIGURE 10. The adapter ring 149 is provided with a die seat 149a in which a slidably removable die 150 is received. The die 150 has an oval aperture corresponding to the lower end 138a of the punch 138. The die 15% is provided with a radially extending key 151 which is received within a keyway 152 in the die adapter 149. A second keyway 153 is also provided in the die adapter. The keyways 152 and 153 angularly correspond to the keyways 136, 136 for the punch key 137. Since the aperture in the workpiece supporting table 33 is relatively large compared to the size of the aperture in the die 151), there is also provided a filler plate 154, shown resting on the adapter 1 .9, the filler plate 154 jointly with the table 33 and the die 150 providing a substantially smooth support surface for the workpiece.

In order to angularly align the punching and stripping assembly 133 with the die 151B, alignment tools such as shown in FIGURE 7, but of proportionately smaller size, are employed. Thus an upper aligning tool replaces the punch and stripping assembly 133 and employs identical interfitting structure carried by a lower alignment tool which replaces the die 150. Thus again, the annular members 135 and 94 may be rotated to a selected position and locked.

The upper end or supporting portions of the upper tool supports 132 and 41 are identical, and the structure employed on the right arms 13211 and 41b is a mirror image of that employed on the left arms 132a and 41a. Thus in FIGURES 12-16 there is shown one clamping mechanism by which the upper tool support is located, guided, clamped, aligned, and pivoted.

Thus the clamping mechanism 42 is illustrated in FIG- URES 12l6 is representative of all such structure included in the punching machine of this invention. However, it is to be understood that in the preferred embodiment of the invention, two such structures are employed which are not concentric with each other, each of which is individually manually detachable and pivotable.

Each of the clamping mechanisms, such as 42, is secured to the frame 31a and is individually and jointly releasable. In FIGURE 12, it is shown that the clamping mechanism receives and clamps mating structure of the upper tool support 41a, presently to be described, and in a similar manner, mating structure of the upper tool support 132 is received and clamped.

When the clamping structure '42 is manually released, as shown in FIGURE 13, the mating structure of the upper tool support may be removed and reinserted. The details by which clamping and release are efiected are best shown in FIGURES I L-16. The clamping mechanism 42 includes a handle-lever 155 having a handle portion 155a rigidly secured as by welding to a lever portion 15517. The handle-lever is pivoted to the frame 31a, also termed herein a member, by a pivot pin 156 for pivoting about an axis which in this embodiment is vertical. There is also included a slidable floating hook 157 which has a hook end 157a which is movable into and out of engagement with a support pin 158 which comprises part of the mating structure of the upper tool support 41. FIGURE 14 illustrates how the hook end 157a clamps the support pin 158 into engagement with the end of a slot in the frame 31a. As best seen in FIG- URE 15, the hook 157 is slidable to a position shown in solid lines where the hook end 157a is both released from the support pin 158 and is displaced away from the slot into the frame so that the tool support arm 41a may be removed therefrom, from the position shown in FIGURE 15 to the position shown in FIGURE 13. Similarly, FIGURE 15 illustrates the position taken by the tool support after it has been reinserted into the frame slot, immediately prior to its being clamped. In order to effect such movement of the hook, cam means are provided which coact between the handle-lever and the hook 157. In this embodiment, the cam means comprises a disc-like cam 159 secured to the handle-lever 155 by any convenient means, a screw being shown for such purpose only in FIGURE 16. The disc-like cam 159 has its center disposed laterally of the pivoting axis of the pin 156 so that the outer periphery of the disc-like cam is responsive to pivoting of the handle-lever 155. The hook 157 at the end remote from the hook end 157a is provided with a recess or aperture in which the disclike cam 159 is received. Thus the inner surface on the hook which defines such recess is in elfect a cammed surface which is engaged by the cam 159 to regulate hook hook movement to effect clamping and detaching relation between the hook end 157a and the support pin 158.

When it is desired to release the clamping mechanism from the position shown in FIGURE 14, the handle-lever 155 is pivoted about the axis of the pin 156. During approximately the first half of the pivotal movement of the handle-lever, the disc-like cam 159 applies a lateral force to the hook 157 at the end remote from the hook end 157a to cause it to pivot in a counterclockwise direction as viewed in FIGURE 14, the pivoting being about an axis on or in the pin 158. Since the disc-like cam moves in an arc, there is also a displacement simultaneously of the hook 157 in a direction which disengages the hook end 157a, as shown in broken lines on FIGURE 15. This displacement continues until an abutment 160 on the hook 157 engages a fulcrum means or pin 161 carried by the frame 31a. Further counterclockwise movement of the handle-lever 155 causes the disc-like cam 159 to act on the hook at a point between the fulcrum pin 161 and the axis of the pin 156, thereby causing the hook to pivot about the fulcrum pin 161 in a clockwise direction to the position shown in solid lines in FIGURE 15. It is thus apparent that this latter movement is in a direction transverse to the initial disengaging movement of the hook 157. Thus the transverse shift of the hook end is effected by engagement between the fulcrum pin 161 and the abutment 160 on the hook 157, the fulcrum pin 161 being located laterally of the hook member 157 and being engaged thereby after the hook end 157 has disengaged the support pin 158.

The support pin 158 is rotatably supported by hearing means 162 in the upper tool support 41, and the frame 31a is cut back as at 163, so that when one of the clamping mechanisms is released, the other clamping mechanism serves as -a pivotal connection, thereby permitting the tool support which is released at one of its arms to pivot about the support pin 158 at the other of its arms. Thus the position of the structure indicated by solid lines in FIGURE 15 permits the tool support 41 to pivot about the clamping mechanism 43 shown in FIGURE 2. When both clamping mechanisms are released, the tool support may be removed as a unit. Conversely, when the clamping mechanism 43 is released, the tool support 41 may be pivoted about the support pin 158 when the parts are disposed as shown in FIGURE 14. Such alternative pivoting is particularly advantageous for various operators of the machine who may be respectively righthanded. or left-handed, the pivoting being performed to swing the punch and stripper assembly out from under the ram 48 to permit substitution of other punch components.

The frame 31a is provided with a horizontal groove 164 within which the handle-level and the hook 157 are disposed. The groove 164 is intersected by the slot 165 into which the support pin 158 is received. Since there are two clamping mechanisms 42, 43, and since each has a slot 165 spaced apart by a fixed distance, the tool support is constructed with two support pins 158 spaced apart a like distance. Each of the clamping mechanisms is provided with a support pad 166 arranged in coplanar relation with each other against which a surface 167 of the tool support 41 engages and rests.

The clamping mechanisms 42, 43 with their mating structures comprise pivotal connections between the frame 31a and the tool support. This particular clamping mechanism thus accurately aligns and locates the tool support in a predetermined position for maintaining its relationship, and hence the angular relationship of a shaped punch supported thereon, wit-h the gaging structure 34 secured to the workpiece supporting table 33. While the slots 165 in the frame 31a receive and guide the support pins 158, the frame acting through the support pads 166 also supports the tool support 41, even though both clamping mechanisms 42, 43 may be in a released position. When the clamping mechanisms are thus tightened, the tool support is guided thereby to a position of accurate alignment with respect to the ram, in which position the clamping mechanism reestablishes the alignment between the punch. and the die, as governed by the universal keying, reestablishes the alignment between the punch and the die concentrically even though no keying be used for a round punch, and reestablishes the distances between the center line of the punch and die means and the various reference surfaces in the gaging, presently to be described.

When it is desired to reclamp the support pin 158, the handle-lever 155 is moved from the solid line position shown in FIGURE 15 in a clockwise direction to the position shown in FIGURE 14. During the initial part of that movement, the cam 159 pivots the hook 157 about the fulcrum pin 161 to swing the hook into the position shown in broken lines. Further pivoting of the handlelever 155 effects a further sliding of the hook into embracing engagement about the pin 158, and simultaneously, a disengagement of the fulcrum pin 161 so that the hook 157 pivots on the support pin 158 during the latter part of the hook movement. The handle-lever 155 has an adjustable finger 168 which engages a roller 169 on a plunger 170 of an electric switch 171. The switch 171 is normally open, such as in FIGURE 13, and when the handle-lever 155 is placed in a clamped position as shown in FIGURES 12 and 14, the finger 168 raises the plunger 170 to close the switch 171. Such a switch is provided for each clamp mechanism 42, 43 and is included in the electrical control circuit, thereby insuring against its operation when either clamp mechanism is not fully closed.

The gaging mechanism 34 with respect to which the disclosed punch and die means are accurately located, is shown in perspective in FIGURE 1. The gaging means 34 are secured directly to the workpiece-supporting table 33, and have a number of reference surfaces against which workpieces and gage components engage. The gaging means 34 also includes structure for directly numerically indicating the distance from these reference surfaces to the center line of the punch and die support means.

More specifically, the gaging means 34 includes a pair of spaced side rail bars 172, 173 which are fixedly secured to the table 33 at opposite sides thereof in a parallel relation to each other. A rack-like member 174 is also supported on the table 33 in parallel relation to the side rail bar 172, and in a preferred embodiment, includes an elongated threaded portion comprising the major central portion thereof, supported for rotation in end bearing portions adjacent to the side rail bar 172.

An elongated rigid means or gage bar assembly 175 is slidably supported by slide bloiks 176 rigidly secured thereto at its ends, on the side rail bars 172, 173, the gage bar assembly 175 extending transversely, namely perpendicularly to, the side rail bars 172, 173. The gage bar assembly 175 is disposed on the upper surface of the table 33. The gage bar assembly 175 is provided with a number of stops which are slidably adjustably supported thereon. The left slide block 176 supports a mechanism generally indicated at 177 for engaging the threaded portion of the member 174. The left slide block 176 also supports a counter mechanism indicated at 178. On the forward end of the member 174 there is a knob assembly generally indicated at 179.

Referring now to FIGURE 17 on sheet 3, certain portions of the gaging means are shown in greater detail. The side rail bar 172 is supported by a flange 180 which extends substantially coextensively therewith and which insures against any significant deflection thereof, the flange 181 being secured to the table 33 in any convenient manner. The slide block 176 is provided with bearing means 181 which actually engage the side rail bar 172. Similar structure is provided at the opposite side of the table. The elongated rigid means generally indicated at 175 is secured to the slide block 176 by any convenient manner (not shown) and is slidable along the upper surface of the workpiece-supporting table 33. The elongated rigid means 175 includes a rigid base member 182 above which and parallel to which there is disposed a rigid back rail bar 183 which at one end is clamped as at 184 and which is supported by a web flange 185 along approximately the right one-half of its length. The forward face of the base 182 comprises a workpiece engaging reference surface which limits the front-to-rear location of a workpiece with respect to the punch and die means. Secured to the base 182 is a gage bar 186 which has a series of gaging apertures 187 uniformly spaced, for example at one inch intervals, and a series of threaded aperatures 188 disposed intermediate the gaging apertures 187. The rigid back rail bar 183 extends in parallel relation to the reference surface on the elongated base 182 and slidably supports a number of stops thereon. These include a number of finger stops 189 and a micrometer-supporting-bracket stop 190.

To position the stops 189 and 190, there is provided a gage plug assembly which includes a plate 191 disposed in flatwise relation to the gage bar 186 and overlying a pair of holes 187, 188. A gage plug 192 is rigidly attached thereto and has a lower end which projects into one of the gaging holes 187, and an upper end which projects therefrom to provide a gaging surface 193 disposed above the gage bar 186. The support plate 191 is further provided with an elongated thumbscrew 194 which has a threaded portion received in the threaded hole 188 which serves to lock the structure in position. While a gage plug 192 alone could be used, the present structure is preferable since it provides a higher degree of accuracy. The gage plug 192 being held against rocking, whatever clearance may be present between the lower end thereof and the hole 187 will not be amplified by a rocking type of movement at the gaging surface 193. Thus with the present structure, whatever clearance is present at the hole 187 with respect to the lower end of the gage plug 192, such will be the greatest error in location of the gaging surface 193. It is to be understood that the gage plug assembly can be moved throughout the length of the gage bar 186 and positioned in any one of the numerous pairs of space-d gaging and threaded holes.

The bracket supports a direct reading gage such as a straight tubular micrometer 195 by its barrel, and

' shown in greater detail.

the spindle 196 thereof abuts the gaging surface 193 of the gage plug 192. It is apparent that as the micrometer is set to various settings, the bracket 190 may be moved along the back rail bar 183 to various positions in each of which the spindle 196 engages the reference surface 193. An abutment member 197 is screwed and pinned to the bracket 190 and has a reference surface 197a for being engaged by an edge of the workpiece adjacent to that which engages the reference surface 182. In addition, the abutment member 197 has an instep providing a second abutment surface 1971: which is spaced from the surface 197a by the thickness of an abutment member 198 forming a part of the finger stop 189. Thus the bracket stop 190 may be employed both for setting individual finger stops 189 ,and thereafter for directly being abutted by the workpiece. Each of the stops 189 and 190 is provided with clamp means for securing the same rigidly to the back rail bar 183 so that gaging impacts applied by the workpiece thereto will not be transmitted to the comparatively more delicate mechanism of the micrometer 195. The details of the micrometer 195 are known in the art and form no part of the present invention.

The reference surfaces 197a, 197b, and the reference surfaces on the abutment finger 198 are all parallel to one another, and to the side rail bars 172, 173, and perpendicular to the reference surface on the base member 182.

Referring now to FIGURE 18, there is shown an end view of the bracket stop 190. The bracket 190 comprises a C-shaped section having a radial opening 199 which is smaller in extent than the diameter of the back rail bar 183. This relationship normally prevents removal, and a clamping screw 200 acts to lock the stop assembly 190 in position on the back rail bar 193. The micrometer assembly 195 is locked in position so that its calibration reads directly, with the position of the gage plug 192, the exact distance from the reference surface 197a to the fore and aft center line passing through the punch and die support means. A setscrew 201 maintains this relationship once it has been established. In order to remove the bracket stop 190 as a unit, the clamping screw 200 is removed first, and then the stop'190 is moved as a unit to a position of alignment with a pair of flats 202, 202 in the back rail bar 183, the

flats 202, comprising portions of reduced size smaller Referring now to FIGURE 19, the finger stop 189 is The finger stop 189 includes a bifurcated body 203 to which a threaded clamp portion 204 is pivoted. A clamping screw 205 biased by a spring 206 keeps the clamping portion 204 and the body 203 in snug engagement'with the back rail bar 183, to permit sliding. Further tightening of the screw 205 precludes movement of the finger stop 189. The abutment member 198 is also pivoted within the bifurcation of the body 203 and extends down to the workpiece supporting table 33. Its forward edge is curved as at 198a to permit a workpiece to enter and raise the abutment l portion of the elongated member 174. To this end, there is provided a pair of confronting clamping blocks 208, 209. Each of these blocks is adjacent to the elongated member 174 and they are disposed on opposite sides thereof. It will be noted that only the clamping block 208 is provided with threads 208a for engaging the elongated member 174. In order to move the blocks toward and from each other, and toward and away from the elongated member 174, there are provided manually operated means which engage the blocks jointly to effect such movement. A U-shaped member comprising a pair of parallel bolts 210, 210 and a block 211 supports a manually operated screw 212. The arms or bolts 210 of the U-shaped member have engagement in a direction parallel to their axes with the block 209 through their heads and with the block or bight portion 211, surrounding the threaded portion of the elongated member 174. The threads of the manually operated screw 212 engage with threads in the block or bight portion 211, and the inner end thereof drivingly engages the other block 208. A pair of springs 213, 213 acts to urge the blocks 208, 209 apart, and an additional spring 214 acts between a portion or bracket 215 which is rigid with respect to the gage bar assembly 175, and the manually operated means in such direction. as to urge engagement between the threads of the block 208 and the elongated member 174. It is apparent that rotation of a knob 216 which is corotatable with the screw 212 will effect simultaneous advance and retraction of the blocks 208 and 209 with respect to each other. In the event that friction should bind one of the blocks, the other block will continue to move until it engages a stop pin. A stop pin 217 is provided for the block 209, while an adjustable stop pin 218 carried by the block 211 is provided for the block 208. The stop pins 217 and 218 also limit the extent which the blocks may be retracted.

As the knob 216 is rotated to bring the blocks 209, 208 together, energy is stored in the springs 213, and some energy is released from the spring 214. As the blocks are moved in the opposite direction, the springs 213 yield up energy to assist in block separation, some energy being then stored in the spring 214.

A particular advantage of the spring 214 is that it insures that the block 209 is the first to be released and the last to be engaged with respect to the elongated member 174.

In a direction parallel to the axis of the elongated member 174, the blocks 208, 209 are retained against any movement by being disposed between a pair of guide blocks 219, 220 secured by screws 221, and suitably pinned as at 222 to the slide block 176. The blocks 208, 209 are thus supported to be moved only toward and from the elongated member 174, and otherwise to be moved jointly with the gage bar assembly 175.

When the blocks 208, 209 are placed in a fully engaged and tightened position, it is apparent that the elongated member 174 will be prevented from rotating and that the gage bar assembly 175 will not be able to slide along the side rail bars 172, 173. When the manually operated means is actuated by the knob 216 so that the block 209 is released but so that the threads of the block 208 still engage the threads of the elongated member 174, sliding movement along the side rail bars is still precluded. However, a rotation of the elongated means 174 will effect limited movement of the gage bar assembly 175 as a unit. Stated otherwise, under this relationship of the blocks, the gage bar assembly may be moved by rotation of the elongated member 174. When the blocks are further retracted so as to fully disengage the threads of the block 208, then unrestricted movement of the gage bar assembly in a fore and aft direction will be permitted.

As a primary means of indicating the fore and aft location of the gage bar assembly 175, the counter mechanism indicated at 178 in FIGURE 1 and shown in greater detail in FIGURE 24 is provided. A mounting plate 223 is secured to the slide block 176, and a supporting block 224 is welded to the plate 223. A rotary counter 225 having indicia wheels is supported thereon and has an input pinion 226 which is driven through an idler 227 by a gear 228 supported on a shaft 229 journaled in the mounting block 224. A gear 230, corotatable with the gear 228 engages the teeth or threads of the rack-like or elongated member 174. The internal details of the counter mechanism 225 are known in the art. The idler gear 227 is supported on a pin shaft 231 carried by the mounting plate 223.

The ratio of the gear train is so selected that movement of the gage bar assembly 175 for a distance will indicate that distance on the counter 225. This is accomplished in a typical example as follows. Ten teeth or threads are provided per lineal inch on the elongated member 174, and forty peripheral teeth are provided on the gear 230. A relative displacement then of four inches is required to obtain one revolution of the shaft 229. One revolution of the shaft 229 produces one revolution of the gear 228, and the gear ratio is so selected that this effects four revolutions of the counter input pinion 226. The right-hand indicia wheel on the counter 225 moves with the pinion 226 at the same rate so that four revolutions are thereby effected, thereby effecting a change of forty units for a four inch displacement. Thus tenths of inches may be read directly on the counter 225. The mechanism is so assembled that when the reference surface on the base member 182 coincides with the center line of the punch and support means, the counter 225 will indicate zero. It is thus apparent that the counter mechanism 178 is fixed to the slide block 176 at one end of the gage bar assembly 175 and that it is geared to the threaded portion of the rack-like member 174 for directly indicating the distance between the reference surface on the base member 182 and the center line of the punch and die means. It is also apparent that as the gage bar assembly is moved back and forth, a continuous indication of the distance referred to will be provided.

In order to position the reference surface on the base member 182 more accurately, the elongated member 174 is made rotatable, is provided with threads, and is provided with. the knob assembly 179 shown also in FIG- URE 23. A rotation of the elongated member 174 while lightly engaged with the threads of the block 208 effects a corresponding change in fore and aft position of the gage bar assembly 175. Likewise, it changes the position of both the mounting plate 223 and the pinion 230 of the counter mechanism by the same amount so that the indication thereon is not affected. The knob assembly 179 includes a knob 232 having peripheral calibrations, and being corotatably secured to an end of the elongated member 174. To this end, the member 174 is provided with a Woodruff key 233 received in a slot 234 in the knob 232. This keying arrangement permits relative axial movement, but precludes relative angular movement therebetween. The periphery of the knob 232 is divided into one hundred equal calibrations, in a typical embodiment, so that thousandths of an inch may be read directly thereon. The elongated member 174 is provided with a bearing portion 174a at each end which is rotatably supported in flange portions 33a of the workpiecesupporting table 33. Preferably, a suitable bearing insert 235 and bearing sleeve 236 is also employed as shown. The bearing insert 235 is secured fixedly by a screw 237 to the table flange 33a. A locking member or nut 238 is carried on the outer end of the elongated member 174 and coacts with a shoulder 239 on the elongated member 174 to clamp the calibrated knob 232, andhence also the elongated member 174 to the table 33 in a selected angular position. When the nut 238 is fully tightened, and the knob 232 is set to a zero position, the counter 225 should also indicate a zero position, or precisely a certain tenth of an inch. Any discrepancy in the indication of the counter mechanism 225 may be alleviated by adding to or subtracting from a number of shims 240. Thus the shims 240 comprise means for adjusting the position of the elongated member or rack-like member 174 in a direction parallel to the axis of the side rail bars 172, 173, to a zero counter position.

Since the indication on the calibrated knob 232 and on the counter 225 is thus synchronized, these elements jointly indicate the magnitude of the distance from the reference surface on the base member 182 to the center line of the punch and die support. The indication on the knob, if any, indicates the magnitude of change from the reading appearing on the counter mechanism. In order to keep all changes positive, so that the knob reading will not be subtracted from the counter reading, there is provided a pair of interengaging pins 241, 242, the pin 241 being carried by the table flange 33a, and the pin 242 being carried by the calibrated knob 232. These pins engage with each other when the knob is in a zero position, and permit movement of the knob only in an increasing direction. They reengage immediately before the knob can be advanced a full revolution to the zero position. Thus a reading typically on the knob is limited to the range between zero and .098 inch. It is apparent that when the locking nut 238 is fully tightened, both axial and angular movement by both the knob and the elongated member 174 is precluded.

In an actual embodiment, the physical extent of the gage bar assembly 175 is several feet. Therefore, it is advantageous also to have the gage bar assembly clamped near its mid-position, namely at a point approximately rearwardly of the punch and die means, since it is at this point that the operators pushing force on a workpiece will tend to cause slight yielding. In view of the high degree of accuracy to which the instant gaging is adapted to perform, it is therefore preferable that such clamping be employed to maintain such accuracy. An example of such a clamping structure is shown in FIGURE 25. At a point near the middle of the back rail bar 183, there is provided a horizontal element 243 which extends transversely to the axis thereof. The table 33 is provided with a locking mechanism which acts on the horizontal element 243 to thereby lock the position of the gage bar assembly 175 with respect to the table 33. This locking mechanism includes a manually rockable shaft 244 disposed beneath the table 33, and having on its rearward end, a cam 245 which is corotatable with the shaft 244. The cam 245 acts on a vertical slide pin 246 to engage and to raise a friction element 247 into clamping relation with respect to the horizontal element 243. The friction element 247 extends perpendicularly to the drawing and is attached by conventional means remotely from the pin 246 to a guide block 248 in which the pin 246 is 'slidable and which is apertured to receive the elongated member 243. At the forward end of the shaft 244, there is provided a bearing block 249 which is secured to the table 33 and which supports a lock screw 250 the point of which is received in a recess 251 in the shaft 244 to prevent axial movement thereof. A handle 252 is carried on the forward end of the shaft 244 at the front of the table 33. As illustrated, the structure of FIGURE 25 is shown in a released position. Movement of the handle 252 in either direction raises the slide pin 246 to clamp the friction element 247 against the horizontal element 243, thereby precluding any horizontal movement of the gage bar assembly 175.

It is apparent that in certain installations, the indication on the counter mechanism 225 will be sufficiently accurate, and that no rotation of the elongated member 174 will be required. Under such circumstances, the member 174 may comprise a rack.

The back rail bar 183 also slidably supports a template follower mechanism 253, and selective reciprocation of the follower mechanism 253 effects a fore and aft movement of the reference surface on the rigid base 182. The follower mechanism 253 is adapted to overlie a template 254 shown fragmentarily in FIGURE 1 and in enlarged cross-section in FIGURE 26, and to engage the workpiece in a manner to effect joint movement therebetween. The workpiece-supporting table 33 is slightly undercut adjacent to the punch and die means for receiving such a template in substantially coplanar relation with the rest of the workpiece-supporting table 33 so that the workpiece can also for certain positions overlie the template 254. The template 254 is located by means of guide buttons 255 and is held securely against the table 33 by a sheet of pressure sensitive tape 256 having a first pressure sensitive coating 257 in engagement with the upper surface of the table 33, and a second pressure sensitive coating 258 in engagement with the lower surface of the template 254. We have found that this type of template attachment is particularly advantageous since there is thus no obstruction provided to free movement of the template follower mechanism 253 or workpiece driven thereby, as has been true in the past with various types of overlapping clamping means employed. We have also found that this mode of attaching the template 254 is extremely reliable and rigidly locates the template in a truly fixed position.

Referring now to FIGURE 27, the operation of the punching machine 30 will be described. A three phase line 259 leads through a master switch 260 and fuses 261 through certain contacts of a motor starter 262 and a thermal overload means 263 to a motor 264 which continuously drives the flywheel-pulley 45. A transformer 265 provides lower voltage for the control circuits.

By manual operation of a start switch 266, the circuit is completed to the coil of the motor starter 262, said circuit including thermal overload contacts 267 and a manual stop switch 268. Completion of the circuit to the coil of the motor starter 262 closes the various contacts thereof which includes a holding contact connected across the starting switch 266. Therefore, any subsequent actuation of the stop switch 268 breaks the circuit to the motor starter 262 to stop the motor 264. For convenience, a power outlet 269 is connected across the secondary of the transformer 265 to energize other accessories, not shown.

Power from the transformer 265 is also directed to a first selector switch 270 which has two positions. In the illustrated position, the selector switch 270 directs power toward a foot switch 271, and in its other position, the selector switch 270 directs power to a switch 272 which forms a part of the template follower mechanism 253. The other side of the switches 271 and 272 are directed to a second selector switch 273. In the illustrated position of the switch 273, it connects the switches 271 and 272 in series with a circuit branch employing two relays and two switches by which single strokes of the ram are effected. In its other position, the selector switch 273 is connected to another circuit branch by which continuous reciprocation of the ram is effected. As mentioned previously, the ram is connected by an electrically actuated clutch to the reciprocating mechanism, the electrically actuated clutch including a solenoid or coil 274. The switches 171, 171 which are responsive to the position of the clamping mechanisms 42, 43, and which are closed as shown when the clamping mechanisms are in a clamped position, are connected in series with the solenoid 274 so that if either clamping mechanism be even partially loosened, the solenoid 274 cannot be energized. Thus it is apparent that if the selector switch 273 be positioned in its other position, and the actuating switch 271 be closed, power will flow continuously through the solenoid 274, so long as the actuating switch 271 is held in a closed position. This is a condition which is particularly advantageous for nibbling operations. It is to be noted that the power for the solenoid passes through the holding contact of the motor starter 262 so that any time that the stop switch 263 is actuated, not only does the motor 264 become deenergized, but also the solenoid 274 is rendered inoperative. Of course, changing the position of any one of switches 270, 271, 273, or 171 also instantly deenergizes the solenoid 274 of the clutch 48.

When the selector switch 273 is in the illustrated position, the solenoid 274 may also be energized through contacts of a control relay 275 which are connected between the holding contact of the motor starter 262 and the solenoid 274. To energize the coil of the control relay 275, the actuator switch, such as 271, is closed, thereby bringing potential to opposite sides of a limit switch 276, also shown in FIGURE 2, which is disposed to be momentarily operated once for each revolution of the flywheel 45. The limit switch 276 is normally open, and when it is momentarily actuated, it completes the circuit to the coil of the control relay 275, thus also closing a holding circuit 277 which bypasses the selector and actuating switches as well as the limit switch 276. Thus the circuit to the solenoid 274 is also closed.

It will be noted that the circuit to the coil of the control relay 275 includes normally closed contacts of a second control relay 278, and the opening of these contacts is utilized to deenergize the holding circuit of the control relay 275, to thereby deenergize the solenoid 274. The control relay 278 includes a coil connected in series with a second limit switch 279. Further rotation of the flywheel closes the limit switch 279 to bring power through the then closed holding contacts of the control relay 275 to the coil of the control relay 278, thereby opening the normally closed contacts in the coil circuit of the control relay 275 and also closing holding contacts of the control relay 278 which are energized through the actuator switches, such as 271. Release of the foot switch 271 thus breaks the holding circuit to the control relay 278 to place it in position for initiation of a second single stroke of the ram.

It is thus apparent that the control circuit provided will regulate the operation of the clutch solenoid 274, and that by proper manipulation thereof, continuous reciprocation of the ram will be provided for a selected period of time, and also single strokes of the ram will be provided even though the actuator switch 271 or 272 is held continuously in a closed position.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. A punching machine comprising in combination: a frame having means adapted to support and to reciprocate punch and die means relatively to each other; a horizontally directed table disposed to support a workpiece adjacent to one of the punch and die means; side rail bar mean fixedly secured to said table; a gage bar assembly slidably supported at its ends on said bar means and extending transversely thereto along the upper surface of said table, said gage bar assembly having a reference surface perpendicular to said side rail bar means for being engaged by an edge of the workpiece, said gage bar assembly including at least one stop slidably adjustable for a distance along the length of said gage bar assembly and having a reference surface parallel to said side rail bar means for being engaged by another edge of the workpiece.

2. In a punching machine having a frame, and support means rigidly secured tothe frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to directly support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; a mechanism carried at one end of said gage bar assembly for selectively holding and releasing said gage bar assembly for free movement with respect to said table; said gage bar assembly including a horizontal element intermediate its ends and extending transversely thereto, and a locking mechanism secured to said table and selectively operative on said horizontal element to lock said gage bar assembly in a selected position and to release said element for free sliding movement with respect to said table.

3. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; a mechanism carried at one end of said gage bar assembly for selectively holding and releasing said gage bar assembly for free movement with respect to said table; said gage bar assembly including a horizontal element intermediate its ends and extending transversely thereto; a manually rockable shaft disposed beneath and secured to said table; a cam corotatably carried by said shaft; and a friction element actuated by said cam and engageable with said horizontal element to lock said gage bar assembly in position.

4. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member rotatably secured to said table and having a threaded portion adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly and operative on said threaded portion to lock and to release said gage bar assembly for free movement with respect to said elongated member, and to enable driven change in the position thereof; and a knob corotatable with said elongated member by which the position of said gage bar assembly may be changed, said knob being calibrated to indicate directly the magnitude of said change.

5. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member rotatably secured to said table and having a threaded portion adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly and operative on said threaded portion to lock and to release the position of said gage bar assembly, and to enable driven change in said position; a knob corotatable with said elongated member by which said position of said gage bar assembly may be changed; a rotatably driven mechanical digital counter fixedly supported on said one end of said gage bar assembly and geared to said threaded portion; said knob being calibrated to indicate directly and jointly with said counter the distance between said reference surface and the center line of the punch and die support means.

6. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; a racklike member secured to said table in a position adjacent to and parallel to one of said side rail bars; a rotatably driven mechanical digital counter fixedly secured to one end of said gage bar assembly and geared to said racklike member; and means for adjusting the position of said rack-like member in a direction parallel to the axes of said side rail bars for effecting precise zeroing of said counter; said counter being operative to directly indicate the distance between said reference surface and the center line of the punch and die support means as said gage bar assembly is moved on said side rail bars.

7. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly and having threaded engagement with said threaded portion for effecting movement of said gage bar assembly thereby; a calibrated knob corotatable with said elongated member for effecting rotation thereof; and a locking member operative on both said knob and said elongated member to clamp said knob and said elongated member to said table, thereby precluding any axial or angular movement of both said knob and said elongated member.

8. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides therof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a refrence surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; manually operable means engaging said blocks for jointly moving said blocks toward and away from each other; only one of said blocks having threads engageable with said threaded portion; said manually operable means being selectively operable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

9. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; a U-shaped member having a pair of arms secured to one of said blocks, said U-shaped member having a bight extending in surrounding relation to said threaded portion; a manually axially movable element extending through said bi ht and drivingly engaging the other of said blocks for jointly moving said blocks toward and away from each other; one of said blocks having threads engageable with said threaded portion; said manually movable element being selectively positionable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

It), In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; spring means continuously urging said blocks apart; manually operable means engaging said blocks for jointly moving said blocks toward each other and for storing energy in said spring means, and for jointly moving said blocks away from each other assisted by said spring means; a stop pin for each of said blocks operative to limit the distance which each block can be retracted from the threaded portion; one of said blocks having threads engageable with said threaded portion; said manually operable means being selectively operable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

11. In a punching machine having a frame, and support means rigidly secured to the frame and adapted to support punch and die means in alignment with each other, the improvement comprising in combination: a horizontally directed table adapted to be secured to the frame independently of said support means, and disposed to support a workpiece intermediate the punch and die means; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion dis posed adjacent to and parallel to one of said side bar rails; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; first spring means continuously urging said blocks apart; manually operable means engaging said blocks for jointly moving said blocks toward each other and for storing energy in said spring means, and for jointly moving said blocks away from each other assisted by said spring means; only one of said blocks having threads engageable with said threaded portion; said manually operable means being selectively operable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assemby, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars; and second spring means acting between said gage bar assembly and said manually operable means to urge said one threaded block toward said threaded portion whereby the other block is the first to be released and the last to be clamped.

12. A structure for accurately positioning a workpiece in relation to a predetermined reference point, compris ing in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; a mechanism carried at one end of said gage bar assembly for selectively holding and releasing said gage bar assembly for free movement with respect to said table; said gage bar assembly including a horizontal element intermediate its ends and extending transversely thereto; and a locking mechanism secured to said table and sclectivey operative on said horizontal element to lock said gage bar assembly in a selected position and to release said element for free sliding movment with respect to said table.

13. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being angaged by an edge of the workpiece; a mechanism carried at one end of said gage bar assembly for selectively holding and releasing said gage bar assembly for free movement with respect to said table; said gage bar assembly including a horizontal element intermediate its ends and extending transversely thereto; a manually rockable shaft disposed beneath and secured 23 to said table; a cam corotata-bly carried by said shaft; and a friction element actuated by said cam and engageable with said horizontal element to lock said gage bar assembly in a preselected position.

14. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; a rack-like member secured to said table in a position adjacent to and parallel to one of said side rail bars; a rotata-bly driven mechanical digital counter fixedly secured to one end of said gage bar assembly and geared to said rack-like manner; and means for adjusting the position of said rack-like member in a direction parallel to the axes of said side rail bars for effecting precise zeroing of said counter; said counter being operative to directly indicate the distance between said reference surface and said predetermined reference point as said gage bar assembly is moved on said side rail bars.

15. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly and having threaded engagement with said threaded portion for effecting movement of said gage bar assembly thereby; a calibrated knob corotatable with said elongated member for effecting rotation thereof; and a locking member operative on both said knob and said elongated member to clamp said knob and said elongated member to said table, thereby precluding an axial or angular movement of both said knob and said elongated member.

16. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; manually operable means engaging said blocks for jointly moving said blocks toward and away from each other; only one of said blocks having threads engageable with said threaded portion; said manually operable means being selectively operable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

17. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; a U-shaped memher having a pair of arms secured to one of said blocks, said U-shaped member having a bight extending in surrounding relation to said threaded portion; a manually axially movable element extending through said bight and drivingly engaging the other of said blocks for jointly moving said blocks toward and away from each other; one of said blocks having threads engageable with said threaded portion; said manually movable element being selectively positionable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

18. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination: a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on opposite sides of said elongated member; spring means continually urging said blocks apart, manually operable means engaging said blocks for jointly moving said blocks toward each other and for storing energy in said spring means, and for jointly moving said blocks away from each other assisted by said spring means; a stop pin for each of said blocks operative to limit the distance which each block can be retracted from the threaded portion; one of said blocks having threads engageable with said threaded portion; said manually operable means being selectively operable to clamp both of said blocks against said threaded portion to preclude movement of said gage bar assembly, to lightly engage the threads of said one block with said threaded portion to enable rotation of said elongated member to reposition said gage bar assembly, and to release both of said blocks from said threaded portion to enable free sliding movement of said gage bar assembly on said side rail bars.

19. A structure for accurately positioning a workpiece in relation to a predetermined reference point, comprising in combination; a table adapted to support the workpiece; a pair of spaced side rail bars fixedly secured to said table at opposite sides thereof in parallel relation to each other; a gage bar assembly slidably supported at its ends on said side rail bars and having a reference surface for being engaged by an edge of the workpiece; an elongated member having a bearing portion rotatably mounted on said table, and having a threaded portion disposed adjacent to and parallel to one of said side rail bars; a mechanism carried at one end of said gage bar assembly, said mechanism including a pair of movable clamping blocks disposed adjacent to each other on op- 

1. A PUNCHING MACHINE COMPRISING IN COMBINATION: A FRAME HAVING MEANS ADAPTED TO SUPPORT AND TO RECIP/ ROCATE PUNCH ANMD DIE MEANS RELATIVELY TO EACH OTHER; A HORIZONTALLY DIRECTED TABLE DISPOSED TO SUPPORT A WORKPIECE ADJACENT TO ONE OF THE PUNCH AND DIE MEANS; SIDE RAIL BAR MEANS FIXEDLY SECURED TO SAID TABLE; A GAGE BAR ASSEMBLY SLIDABLY SUPPORTED AT ITS ENDS ON SAID BAR MEANS AND EXTENDING SUPPORTED AT ITS ENDS ON SAID BAR MEANS FACE OF SAID TABLE, SAID GAGE BAR ASSEMBLY HAVING A REFERENCE SURFACE PERPENDICULAR TO SAID SIDE RAIL BAR MEANS FOR BEING ENGAGING BY AN EDGE OF THE WORKPIECE, SAID GAGE BAR ASSEMBLY INCLUDING AT LEAST ONE STOP SLIDABLY ADJUSTABLE FOR A DISTANCE ALONG THE LENGTH OF SAID GAGE BAR ASSEMBLY AND HAVING A REFERENCE SURFACE PASRALLEL TO SAID SIDE RAIL BAR MEANS FOR BEING ENGAGED BY ANOTHER EDGE OF THE WORKPIECE. 